The overall objectives of the Animal Core are to provide animals to the various projects in the Center, and to organize and store tissue from non-human primates as needed by the projects in the Center. Many of the projects described in this grant will use animal models of self-administration to study long-term neuroadaptations as a consequence of exposure to drugs of abuse. Rats will be trained to self-administer cocaine, heroin, or cocaine and heroin (speedball) for varying lengths of time under different schedule conditions coupled with various periods of deprivation, in addition, rats treated with novel irreversible ligands at the monoamine transporters will be studied behaviorally in locomotor activity studies and prepared for autoradiographic analysis. Finally, the Animal Core will be responsible for proper sacrifice, brain collection, tissue storage, and redistribution of brains from non-human primates used in various projects, when necessary. The specific goals of the Animal Core are as follows: 1. Provide experimental animals to subprojects 0001, 0008, 0011, and 0012 that have particular histories of self-administration and deprivation. 2. Examine the locomotor-altering effects of novel compounds (administered i.c.v.) produced by the Chemistry Core. 3. Provide subjects that have been treated with these novel compounds (administered i.c.v.) to subproject 0001 for autoradiographic analysis. 4. Collect and store brain tissue from non-human primates (from subprojects 0012, 0003, and 0009) when the need arises, and redistribute the tissue to subprojects for neurobiological investigation.